Background Tibet, a region where average elevation is above 3500 m and socio-economic development is relatively lower, was not included in National Oral Health Survey over decades. The cross-sectional study aimed to investigate the status of dental caries and associated factors in Tibetan adults. Methods Participants aged 35–44, 55–64 and 65–74 years were selected. Decayed, missing, and filled tooth (DMFT), decayed and filled root (DF-Root) and root canal index (RCI) were used to evaluate dental caries. Questionnaire survey on demographic information, socioeconomic status, dietary habits, and oral health knowledge and behavior was conducted. Mann-Whitney U test, logistic regression were used for the statistical analyses. Results A total of 446 participants were enrolled in the survey. Of these: 222 (49.8%) were females, 224 (50.2%) were males; 149 (33.4%), 151 (33.9%), 146 (32.7%) were aged 35–44, 55–64 and 65–74 years respectively. The mean DMFT (SD) was 7.62 (4.84), 12.46 (8.16), and 21.38 (8.93). The filling rate was very low in all age groups (1.77%, 0.98%, 0.45%). The mean DF-Root (SD) was 0.50 (1.04), 1.04 (2.02), 1.32 (2.14), respectively. Root caries index was 42.27, 44.78 and 57.60%. Older age (65–74 age group) was positively associated with crown caries (odds ratio = 31.20, 95% confidence interval: 10.70–90.96). College degree and above and brushing teeth at least once a day were negatively associated with crown caries (odds ratio = 0.28, 95% confidence interval: 0.09–0.89; odds ratio = 0.39, 95% confidence interval: 0.21–0.72, respectively). Rural area, high income level and brushing teeth at least once a day were negatively and tooth with attachment loss was positively associated with root caries. Conclusions The status of dental caries in the adults in Tibet is severe and the treatment rate is very low. The study suggests a correlation between crown caries and the variables age, level of education and frequency of tooth brushing; correlation between root caries and residence, income level, frequency of tooth brushing and exposed root surfaces. These findings could be as reference to develop community based interventions to reduce the prevalence of caries in Tibet.

Background The caries-preventive effect of topical fluoride application has been corroborated by a number of clinical studies. However, the effect of fluoride on oral microecology remains unclear. Objective To monitor the effect of fluoride on dental plaque microecology and demineralization/remineralization balance of enamel initial caries. Methods Three-year-old children were enrolled and treated with fluoride at baseline and 6 months. International Caries Detection and Assessment System II indices of 52 subjects were measured at baseline, 3, 6, and 12 months. Supragingival plaque samples of 12 subjects were collected at baseline, 3 and 14 days for 16S rRNA sequencing. Results Changes in microbial community structure were observed at 3 days after fluoridation. Significant changes in the relative abundance of microorganisms were observed after fluoride application, especially Capnocytophaga , unidentified Prevotellaceae and Rothia . Functional prediction revealed that cell movement, carbohydrate and energy metabolism were affected significantly after fluoride application. Fluoride significantly inhibited enamel demineralization and promoted remineralization of early demineralized caries enamel at 3 months. Conclusion Fluoride application significantly inhibited the progression of enamel initial caries and reversed the demineralization process, possibly by disturbing dental plaque microecology and modulating the physicochemical action of demineralization/remineralization. This deepened our understanding of caries-preventive effects and mechanisms of fluoride.

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Objectives: The ongoing outbreak of novel coronavirus (2019-nCoV) infection (COVID-19) has been declared as a global pandemic by the World Health Organization. It is a highly contagious disease that poses a grave threat to human health. Dental practice involves close contact with the airway and dental procedures entail generation of intense aerosol sprays; the virus particles can survive within small droplets in the air for several hours. Thus, dental practice is associated with a high risk of cross infection. This article describes the patient management process and its performance at the outpatient department of a specialized dental hospital during the COVID-19 epidemic in Xi'an, China. The objective is to provide a reference for management protocols for dental clinics and dental specialty centers across the world. Methods: A specialized management protocol for staff, patients, and material management for dental clinic during the epidemic was implemented since February 3 2020. The numbers of outpatient visits, distribution of oral diseases, demographic characteristics of patients, and COVID-19 infection among patients and staff from February 3 to March 15 are described. Results: The management protocols at the dental clinic were tailored according to the level of national emergency response for COVID-19. The number of physical consultations at the hospital was effectively controlled with use of online consulting service. Dental emergency patients were managed safely. Conclusion: The management protocol and infection prevention and control strategies adopted at our institution are effective in treating dental emergencies while controlling the spread of COVID-19 virus in oral clinics.